3rd Generation (3G) is a communication method that provides a wireless Internet service through a base station, and wireless fidelity (Wi-Fi) is a communication method that provides a wireless Internet service using an access point (hereinafter, referred to as an AP). Portable terminals such as smartphones and tablet PCs are able to use wireless Internet services using the 3G or Wi-Fi in any time and place. However, in the case of the 3G, users should pay for the use of the Internet, and, in the case of the Wi-Fi, users are free to use the Internet. In recent years, many open places such as public places are providing the Wi-Fi service.
However, the 3G provides a safe Internet service from the perspective of security, whereas the Wi-Fi uses the AP to provide the Internet service and thus does not guarantee high reliability about security of portable terminals.
For example, if an attacker such as a hacker disguises its terminal as an AP, it is difficult for a portable terminal to recognize that the AP is the attacker's terminal. Therefore, the portable terminal may access such an AP. In this case, the attacker may steal information stored in the portable terminal from the user of the portable terminal. Therefore, there is a need for a method for distinguishing between an attacker terminal which is disguised as an AP (hereinafter, referred to as a “fake AP”), and a real AP.